It is considered that glutamic acid and aspattic acid which are stimulative amino acids are responsible for degeneration and necrocytosis of cerebral nerve cells caused by cerebral ischemia due to cerebral infarction, cerebral hemorrhage, suspension of heart beat, operation of the lung, cerebral injury and the like as well as anoxia. However, there are many unclear points in the mechanism thereof. Although a lot of efforts have been made heretofore so as to investigate antagonists of glutamate as the means for inhibiting degeneration and necrocytosis of cerebral nerve cells, any effective and satisfactory medicine has not yet been found out.